This invention relates, in general, to an interface adaptor for use between a hot runner manifold and a machine nozzle of an injection molding machine and is particularly, but not exclusively, applicable to injection molding system configurations which employ a centre section carrier (or a stack mold arrangement) to permit the use of multiple molds for increased productivity, simultaneous overmolding operations or the like. The present invention also pertains to a method of disassembly of a hot runner adaptor to permit cleaning of the hot runner.